Stoker



Jan. 8, 1946. c, M JESPERSON 2,392,480

STOKER Filed June 3, 1943 5 SheetsSheet l INVENTUR CLARENCE M. JE EPEHEUN BY I? AT T RNEY Jan. 8, 1946. r c M. 'JEsPERsoN 2,392,480

STOKER Filed June 3, 1943 5 sheets-sheet 2 I 'INVENTUR E1 5 CLARENCE NLJEEFERBUN ATT RNEY Jan. 8, 1946. c. M, JEsPERsoN STOKER Filed June 3,. 1945 5 Sheets-Sheet S INVENTDR ELAREN ENJESFERSUN BY v AT [1 EY' Jan; 8, 1946.

c M. JESPERSON STOKER Filed June 5, 1943 5 Sheets-Sheet 4 CLARENCE M.JE.EFER'SDN Jan. 8, 1946. c. M. JEASPIEI-QQSON STOKER Filed June 5, 1945 5 Sheets-Sheet 5 I II I I II 11/11/11 INVENTUR CLARENCE M. JESF'EREEIN AT ANE Patented Jan. 8, 1946 UNITED STATES PATENT OFFICE STOKER Clarence .J'esperson, A-nniston, .Ala.

Application June 3, 1943', Serial No. 489,447

7 Claims.

My'invention relates to stokers, more particularly to stokers 'of the spreader ty e; and has for an object the provision of apparatus of the .character designated which shall be simple or design, economical of manufacture, embody improved fuel distribution means; and'be sturdy and rugged in operation and easily'regulated.

Further objects of my invention are to provide a stoker which shall include improved rotary spreader means adapted to distribute fuel evenly over a wide fuel bed; a means for varying the trajectory of the fuel discharged from the spreaders and so regulate its distribution longitudinally of the fuel bed; improved means for supplying fuel to the fuel spreaders; and means for limiting the area over which fuel is discharged by the spreader means whereby any selected zone of the fuel bed may be cut off from fuel and cleaned without interfering with the feed to other zones.

My invention still further contemplates the provision of a rotary spreader adapted to cooperate with a substantially horizontal distribution plate to discharge fuel on to the fuel bed, said spreader having a curved active face adapted to provide an even distribution of fuel over the fuel bed.

A more specific object of my invention is to provide an improved rotary spreader having a curved active face, the curvature increasing withv the radius of the spreader arms.

A further object of my invention is to provide a stoker having feeder means embodying a distribution plate, and a pair of rotary spreaders adapted to cooperate with the plate to discharge fuel into the furnace, said spreaders having radial arms mounted to rotate above the distribution plate.

The invention by which the foregoing and other objects are attained is illustrated in the accompanying drawings, forming a part of this application, in which Fig 1 is a front elevational view of the assembled stoker; I

Fig. 2 is a sectional view taken along the line IIII of Fig.

Fig. 3 is a side elevational view of the assembled stoker; V I v Fig. 41s a sectional view of the feed screw housing taken along the line IV-IV of Fig. 3; v

Fig. 5 is a sectional vplan view of the distribution plate and spreaders taken along the line V--V of Fig. 3;

Fig. 6 is a diagrammatic sectional plan view of the spreaders with a furnace fuel bed illustrating the distributionof fuel therein; ,7 r g V Fig. 7 is a detail sectional view showing the furnace opening and the discharge edge of the distribution plate;

.Fig. 8 is a. detail view of one of the zoning bars; Fig. '9 is a detail view of one of the spreaders showing one form of its development; and

Fig. 10 is a bottom .plan view of th feed openper II, having the usual feed screw housing I:

at the bottom, in which a feed screw ['3 is located. The housing is provided with a delivery opening [4 at the bottom-in which is located an adjustable cut off plate l6. See Fig. 10. The cut off plate is supported on lateral guides and :is provided with a V-shaped delivery opening 11. Connected to the out 01f plate is an adjusting rod I8 mounted in a bracket [9 on the underside of the housing whereby the point of delivery of fuel may be varied.

The feed screw I3 delivers fuel into a spreader housing 2.1 which has a top opening 22 to receive fuel from the feed screw and a side opening 23 through which fuel is discharged into the furnace. Located within the spreader housing 2| are two rotary spreaders 24 and 26 (see Fig. 5.) to be described more Particularly hereinafter, which are adapted to discharge the fuel through the side opening 23 of the housing. Mounted within the spreader housing 2| beneath the spreaders 24 and 26 is a distributionplate 2.1 with which the spreaders are adapted to cooperate. The plate 21 is adjustable vertically by means vof set screws 28 and 29 passing upwardly through the bottom of the housing 2| and is maintained in such a position that the spreaders .just clear it without dragging. As shown, the distribution plate 21 and spreaders 24 and 2B are mounted horizontally, but if desired they may be tilted so that the fuel discharged by the spreaders may be thrown a greater or lesser distance. A cast rim 25, within the spreader housing 2|, forms the outer boundary of the paths of rotation of the spreaders '24 and 26.

Pivotally mounted in brackets 3| and 32 along the discharge edge of the distribution plate 21 is a discharge lip 33 which has a lower depending flange 34. A set screw 36., mounted in a flange 31, on the underside of the spreader housing 2| bears against the flange 34 and is adapted to adjust the angular position of the discharge lip 33,, and thus change the trajectory of fuel being discharged by the spreaders. 1

At 38 I show a conduit through which the usual v supply of primary air for combustion is supplied.

In order to keep the distribution plate 21 cool and to keep fine coal from settling in the discharge opening, I connect conduits 39 and 4| to the conduit-38 and pass themrinto the feed housing 2| through openings 42 and 43 beneath the distribution plate 21. The air thus admitted is discharged along the discharge edge of the distribution plate 21 through the space 44 between the distribution plate and the adjustable lip 33, and blows away the fines which might otherwise settle in the discharge opening.

Adapted to fit in brackets 46 across the dis charge opening 23 of the housing 2| are zoning;

bars 41, two being provided. See Fig. 8. The zoning bars are each provided with graduations 45 to indicate their positions. By adjusting the positions of the zoning bars 41, any desired area of the fuel bed 48 defined by one wall of the furnace.

into the feed housing 2l and engaged by the I spreaderfl is discharged by the spreaderifi on to the other half of the fuel bed. The half of 'the fuel ,bed controlled by the left hand zoning bar 41 may thus be cleaned. The action thus described; would be the same if only one spreader,

instead of two, were employed as the area cone is adjustable vertically with respect to its base For the purpose of adjusting the motor, I show an adjusting screw 68 and manual adjusting means 69 on the screw. At H ,I show an adjustable V-belt pulley which connects with the belt 12 to a pulley 13 on the worm shaft 64. By adjusting the distance between the pulleys H and 13, I can vary the speed at which the stoker is driven.

On the outer end of the worm shaft 64 is a variable V-belt pulley 14 which connects through a belt 16 with a pulley 11 mounted on a lower Worm shaft 18. The worm shaft 18 is provided with a worm 19 which meshes with the worm gear 8| on the end of the feed screw shaft 82, and

thus drives the feed screw.

From the foregoing description, the operation of my improved stoker will be readily understood.

Fuel is supplied to the hopper II and moves by V gravity through the open bottom of the hopper into the feed screw housing l2, and is moved by the feed screw l3 to the opposite end Where it is delivered through the bottom opening l6 into the spreader housing 2|. The V-shaped opening in the feed screw housing is very important in causing a uniform rate of discharge of fuel from the feed screw housing onto the distribution plate. It is also advantageous to regulate, by means'of the rod IS, the position of the cut off plate IE to accommodate the service to which the stoker is subjected. Where the average demand for fuel is heavy, the out off plate I6 is movedto provide an earlier discharge than in the case of a light average demand; The distribution plate 21 is trolled by the zoning bars would be the same.

For convenienceof manufacture and operation, I preferably employ 'twospreaders;

QReferring now particularly to'Fig. 9, each of the spreaders has curved radial arms 49 and 5!. For even distribution of fuel on the fuel bed, I have found it very important that the active faces 52 and 53 of the arms 49 and 5 1, respectively,

. should be convexly curved and preferably have a ,face with a curvature which is the arc of a circle,

do not give as satisfactory distribution or tra: jectory to the fuel being distributed. To those skilled in the art, it will'at once be seen that a ,number of curved surface might be developed for the active faces of the arms 49- and 5|. For example," the parabola, hyperbola, ellipse, cate adjusted by means of set screws 28 and 29 so that it just clears the spreaders 24 and 26., The

spreaders rotate in opposite directions, as shown by the arrows in Fig. 5, engage the fuel and distribute it evenly over the entire fuel bed. It 1s contemplated that primary air for combustion will be supplied beneath the grate 80 shown in Fig. '1 and that secondary air will be supplied beneath the distribution plate 21 as heretofore'described. If it be desired to out off the supply of fuel from either side of the fuel bed 48 in'the furnace, the zoningbars 41 are placed in the brackets 46 in front of the side to be cut out. I {Increafter all fuel will be discharged by one spreader, the otherspreader simply moving'its portion of the fuel into the path of the other spreader. The

rotational speed of the spreaders and conse tor 66, thus-varying the distance between the nary, cycloid, logarithmic spiral, and other curves 0 all embody the principle of a varyingcurvature and might be adapted for the purpose. By way of example, I show in Fig. 9 the development of surfaces whichl have successfully employed, the

' mounted on a worm shaft 64 extending horizone tally across between the hopper H and the furnaoe front} I V a I My improved stoker is driven by means of a motor 6 6, mounted on thefurnace front. "I, and

variable-V-belt pulley H and the pulley 13.

From the foregoing it will be apparent that ,I

have devised an improved stoker which is simple and sturdy of design, reliable in operation; and

which employs greatly improved fuel distributhat only such limitations shall be placed there upon as are specifically set forth in the appended claims.

WhatI cl'aimis: I 1. In a spreader type stoker, fuel spreading means comprising adistribution plate, a pair of spreaders mounted to rotate above, the plate-and having: radialspreader arms rotating in interengaging paths inthe same plane, a housing'for' for the discharge of fuel, means to supply fuel to the spreader housing, zoning bars adapted to fit across the discharge opening to limit the area over which fuel is discharged, and an adjustable lip along the discharge edge of the distribution plate adapted to vary the trajectory of fuel discharged.

2. In a spreader stoker, fuel spreader means embodying spreader arms adapted to rotate in opposite directions in interengaging horizontal zones of rotation, parallel vertically disposed shafts upon which the arms are mounted, means to rotate the shafts in opposite directions, a spreader housing having a discharge opening on one side and an opening in the top to receive fuel, a feed screw and housing therefor termi-. nating between the shafts above the spreader arms and adapted to discharge fuel into the spreader housing, and a discharge plate in the bottom of the screw housing above the spreader housing and having a V-shaped discharge opening therein.

3. In a spreader stoker, fuel spreader means embodying spreader arms adapted to rotate in opposite directions in interengaging horizontal zones of rotation, parallel vertically disposed shafts upon which the arms are mounted, means to rotate the shafts in opposite directions, a spreader housing having a discharge opening on one side and an opening in the top to receive fuel, a feed screw and housing therefor terminating between the shafts above the spreader arms and adapted to discharge fuel into the spreader housing, a discharge plate having a V-shaped discharge opening in the bottom of the feed screw housing, and means to adjust the position of the discharge plate longitudinally of the feed screw housing.

4. In a spreader stoker, spreader means comprising a substantially horizontal distribution plate, means to feed coal onto said plate and a spreader embodying a vertically disposed rotary shaft and radial arms on said shaft adapted to rotate in close proximity to the distribution plate, the leading side of each of said arms comprising a convex involute curve generated from a circle having a diameter slightly less than the length of the arm.

5. In a spreader stoker, a rotary spreader rotating about a vertical axis and embodying radial arms having continuous convexly curved active faces in which the radius of curvature decreases from the center of rotation outwards.

6. In a spreader type stoker, a distribution housing, having an opening in the top for receiving fuel and another along one side for discharging fuel, a distribution plate adjustably mounted in. the housing to provide an air space therebeneath, means to supply fuel to said plate through said top opening, 'a pair of spreaders having arms mounted to rotate above said plate with interengaging paths of rotation and to discharge fuel through the said opening, a discharge lip mounted in the discharge opening in spaced relation to the distribution plate to provide an air passage therebetween, and means to supply air under pressure beneath the distribution plate.

'7. A spreader stoker as defined in claim 1 in which the distribution plate is adjustably mounted in the housing in spaced relation to the bottom thereof, and the adjustable lip is mounted in spaced relation to the discharge plate to provide an air passage therebetween, together with means to supply air under pressure to the housing beneath the distribution plate.

CLARENCE M. JESPERSON. 

